US 2013/0253387 A1 discloses a system for applying vibratory energy to pathologic material in a treatment area of a body. The system comprises an energy source configured to provide an energy signal, a piezoelectric transducer configured to receive the energy signal and an effector operatively coupled to the transducer, wherein the effector has a proximal end connected to a handle and a distal portion configured to apply the vibratory energy to the pathologic material. The system further comprises a cannula having a longitudinal passage to receive at least a portion of the effector and being configured to expose at least the distal portion of the effector to the pathologic material. The transducer is configured to transfer the vibratory energy through the effector to the pathologic material.
Placement of a lattice of radioactive/energy sources inside a cancerous tissue is a form of radiation therapy used for organs such as prostate, lung, breast, head and neck, etc. The position of these sources are preoperatively planned to attain a good coverage of the cancerous tissue with radiation while having a tolerable dose on the surrounding healthy tissue. Source placement errors are common due to factors such as tissue motion and deformation, needle bending, human error, etc.
An example is low-dose-rate (LDR) prostate brachytherapy. LDR prostate brachytherapy entails permanent placement of radioactive seeds inside the prostate to kill the cancer via radiation. The procedure is conventionally performed under transrectal ultrasound (TRUS) guidance. Accurate placement of the seeds leads to better treatment outcome and less toxicity. However, deviations from the plan are inevitable due to problems such as prostate motion and deformation caused by needle insertion, prostate edema, needle bending and human and calibration errors. In current practice, quantitative dosimetry is performed post-operatively using CT images. At this stage, significant deviations from the plan, if detected, should be fixed by repeated treatment which is costly and time consuming.
Accurate localization of the implanted sources with respect to the target anatomy can result in adaptive planning and delivery which can significantly increase the treatment quality. In order to achieve this, the delivered dose to the target and organs/body tissue at risk needs to be measured and monitored in real-time. The treatment plan may then be adapted based on the measured dose to deliver optimal dose coverage.
In many procedures, source placement is performed under real-time ultrasound imaging. In this context, a localization of the sources in the ultrasound coordinate system would allow for a huge improvement in therapy delivery and treatment results. To this end, source localization in ultrasound B-mode images that are used for visual guidance has been tried, so far unsuccessfully. Source localization in ultrasound is hindered by low quality of ultrasound images, shadowing, missing sources and false positives due to calcifications and air bubbles.
Electromagnetic (EM) tracking technology has been suggested to detect the source position at the time of deposition and record the position of needle tip. However, the EM technology is prone to error due to magnetic field interference from a plethora of metallic objects in the operating room. Moreover, the EM coordinate system should be registered to the US coordinate system for dosimetry.